JP7343532B2 - finishing composition - Google Patents

Description

FIELD OF THE INVENTION This invention relates generally to finish compositions, and more specifically to finish compositions for the processing of polyacrylonitrile carbon fiber precursors.

Carbon fiber has been used in a variety of structural applications and industries because of its desirable properties. For example, carbon fiber can be formed into structural parts that combine high strength and stiffness while being significantly lighter than metal parts with comparable properties. One common method for preparing carbon fibers is to convert polyacrylonitrile (PAN) precursor fibers in a multistep process in which the precursor fibers are heated, oxidized, and carbonized to produce fibers that are greater than 90% carbon. It is to be. The resulting carbon fibers can be formed into high-strength composites for structural applications, used in pure form for electrical and frictional applications, or further processed for adsorbents, filters, or other applications. be able to. In particular, composite materials have been developed in which carbon fibers serve as reinforcing materials for resin, ceramic, or metal matrices.

PAN precursor fibers are typically produced by melt spinning or by solvating the precursor polymer in organic and/or inorganic solvents such as dimethyl sulfoxide, dimethyl formamide, zinc chloride or sodium thiocyanate solution to form a spinning solution. It is prepared by For example, a spinning solution may be formed from water, acrylonitrile polymer, and sodium thiocyanate in an exemplary respective weight ratio of about 60:10:30. This solution can then be concentrated by evaporation and filtered to provide a spinning solution. The spinning solution is passed through a spinneret using various spinning processes such as dry, dry/wet or wet spinning to form polyacrylonitrile precursor fibers. After being discharged from the spinneret, the spun filaments are cleaned. In some embodiments, spun filaments can be stretched in hot water and steam to several times their original length.

After the fibers have been cleaned, they are subjected to chemical treatments that are typically applied to the fibers. Chemicals, process oils, or "finishes" include aqueous solutions or emulsions that may contain lubricants and antistatic agents to help improve fiber handling during subsequent production of carbon fibers. Examples of lubricants include siloxanes, esters, among others. Silicones are one of the most common finishing compositions used to treat PAN precursor fibers. Examples of typical silicones include polydimethylsiloxane, silicone oil, and polysiloxanes such as ethoxysiloxane. Amino- or epoxy-modified silicone emulsions are finishing compositions that can be used to improve the heat resistance of fibers. In particular, functionalized polysiloxanes with amino or epoxy groups are known to reduce the heat released during oxidation/stabilization of PAN precursor fibers. As a result, this helps to prevent or reduce fiber fusion during the carbonization process.

It is also important that a sufficient and uniform amount of the finishing composition is applied to the surface of the fibers to provide the desired properties. If the finishing composition is not applied uniformly, defects can occur in the resulting carbon fibers.

Therefore, there remains a need for improved finishing compositions for the processing of PAN precursor fibers.

Embodiments of the present invention are directed to improved finishing compositions for the treatment of textiles, particularly for the treatment of polyacrylonitrile (PAN) precursor fibers. In one embodiment, the present invention provides a finishing composition comprising a silicone oil, water, an emulsifier, and a dicarboxylic acid with a molecular weight of less than 1,000 g/mol and a pKa of about 1-4.

The use of silicone oils, including epoxy-modified silicones and amino-modified silicones, is commonly used in finishing compositions for the treatment of PAN precursor fibers. The application of such siloxanes to PAN precursor fibers is usually carried out using water emulsions. One of the most effective ways to prepare aqueous emulsions, such as amino-modified siloxanes, is to use weakly acidic species (e.g., with a pKa of 4 to 5) in the composition.

In the case of amino-modified siloxanes, addition of weakly acidic species forms salts/complexes with the amino groups of the siloxane. The formation of the salt complex greatly improves the water solubility of the siloxane and also helps to prevent the amine groups from reacting at elevated temperatures, and this reaction at elevated temperatures is important for drying in PAN fiber production lines. It is known to cause gelling/gumming and build-up of silicone materials on rolls.

Although weakly acidic groups help prevent undesirable reactions of the amino groups at elevated temperatures, it has been found that weakly acidic groups do not bond properly with the amino groups of siloxanes. As a result, the fibers are not adequately protected at elevated temperatures such as those experienced during drying of the fibers. To address this issue, it may be desirable to include antioxidants in the finishing composition. However, the inclusion of antioxidants does not address all issues related to protection of amine groups in siloxane materials.

Furthermore, phase separation of emulsions in finishing compositions can also occur at elevated temperatures as a result of decomposition of acid-amine complexes/salts and by thermal decomposition/evaporation of weakly acidic species. In particular, the acid-base salt/complex groups that helped form the high quality emulsion disappear and the silicone material begins to separate from the rest of the emulsion. Furthermore, when utilizing low molecular weight carboxylic acids as weakly acidic species, these species can be lost due to evaporation at elevated temperatures.

Phase separation of the silicone oil from the emulsion is highly undesirable since it can lead to non-uniform distribution of said oil on the individual filaments, resulting in areas of high and low silicone oil content. Areas of filaments that do not have a protective coating of finishing composition in sufficient amounts tend to fuse with other filaments as a result during carbon fiber manufacturing. Such filament fusion can lead to the formation of stress points that are susceptible to damage during the tow drawing process of carbon fiber lines. Excessive damage to individual filaments in carbon fiber tow is known as "fuzz" and is highly undesirable.

Advantageously, by including a dicarboxylic acid with a pKa of about 1-4 and a molecular weight of less than 1000 g/mol, the inventors have solved the problems associated with phase separation, such as amino functional groups on the PAN precursor fibers. It has been found that the undesirable reactions of the functional groups in the present invention are overcome.

In one embodiment, an embodiment of the present invention provides a finishing composition that includes a polysiloxane, an emulsifier, water, and a dicarboxylic acid with a pK _a of about 1-4 and a boiling point of 200-400°C.

In some embodiments, the finishing composition may further include a monocarboxylic acid with a pK _a greater than 3.7, such as from 3.77 to 5.0. In some embodiments, the monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, hydroxycarboxylic acids with up to 4 carbon atoms, such as glycolic acid and selected from the group consisting of lactic acid;

In some embodiments, the composition further includes a viscosity modifier such as an aminocarboxylic acid material. In one embodiment, the viscosity modifier comprises β-alanine.

In one embodiment, the dicarboxylic acid has the formula:

has

where R ₁ is absent or a saturated or unsaturated, straight-chain or branched, aromatic, substituted or unsubstituted hydrocarbon group,

Y ₁ and Y ₂ are independently nitrogen, oxygen, sulfur or phosphorus, hydrogen, a C ₁ -C ₆ alkyl group, or an alkoxy group,

X ₁ and X ₂ are independently one or more hydrogen atoms, a metal, a quaternary amine, or a hydrocarbon group having up to 6 carbon atoms, and the hydrocarbon group is an alkyl group, an alkylene group , or aromatic groups, which may be branched or straight chained and optionally have one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur and phosphorous.

In certain embodiments, R ₁ is a saturated straight alkyl chain having 2-3 carbon atoms.

In certain embodiments, R ₁ is a saturated branched alkyl chain having 2 to 4 carbon atoms.

In certain embodiments, R ₁ is a saturated straight or branched alkyl chain substituted with one or more nitrogen, oxygen, sulfur or phosphorous containing groups, and the straight alkyl chain has up to 6 carbon atoms. It is individual.

In certain embodiments, R ₁ is an unsaturated straight alkyl chain having up to 6 carbon atoms.

In certain embodiments, R ₁ is an unsaturated branched alkyl chain having up to 6 carbon atoms.

In certain embodiments, R ₁ is an unsaturated straight group having up to 6 carbon atoms and substituted with one or more of a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, or a phosphorus-containing group. The chain is an alkyl chain.

In certain embodiments, R ₁ is an unsaturated branch having up to 6 carbon atoms and substituted with one or more of a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, or a phosphorus-containing group. The chain is an alkyl chain.

In certain embodiments, R ₁ includes one or more polyethylene or polypropylene glycol groups.

In certain embodiments, R ₁ is optionally substituted with one or more of an alkyl group having 1 to 6 carbon atoms, a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, or a phosphorus-containing group. It is an aromatic group.

In certain embodiments, R ₁ includes one or more of an alkene, alkyne, alcohol, carbonyl, ether, amine, amide, phenyl, benzene, furan, pyridine, or pyran group, or an imidazole group.

In certain embodiments, X ₁ and X ₂ are independently hydrogen, alcohol, or phenol.

In some embodiments, X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. In certain embodiments, X ₁ Y ₁ includes an amine or amide group and at least one of X ₂ Y ₂ includes an OH group.

In some embodiments, the finishing composition comprises a monocarboxylic acid with a pK _a1 greater than 3.7, particularly greater than 4.

In some embodiments, the dicarboxylic acid has a pK _a of about 2-3.5, such as a pK _a of about 2-3.

In some embodiments, the dicarboxylic acid has a molecular weight of less than about 1,000 g/mole, such as about 100-600 g/mole or about 125-250 g/mole.

In some embodiments, the dicarboxylic acid has a boiling/decomposition point of 200-450°C, such as about 200-350°C.

In some embodiments, the dicarboxylic acid is DL-tartaric acid, L-tartaric acid, D-tartaric acid, fumaric acid, mesaconic acid, oxamic acid, succinic acid, 2-methylsuccinic acid, L-malic acid, DL-malic acid, D-malic acid, aspartic acid, mesooxalic acid, muconic acid, oxaloacetic acid, glutamic acid, diglycolic acid, iminodiacetic acid, 2,2'-oxydipropanoic acid, 3,3'-oxydipropanoic acid, 2,2 '-[1,2-ethanediylbis(oxy)]bis-acetic acid, 3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid, 3,3'-[oxybis(ethane-2,1- diyloxy)] dipropanoic acid, poly(ethylene glycol) bis-acetic acid, polyethylene glycol bis(carboxymethyl) ether, polyethylene glycol dioic acid 600, chelidonic acid, dipicolinic acid, 2,5-furandicarboxylic acid, isophthalic acid, terephthalic acid, Orthophthalic acid, trimesic acid, 1,4-phenylene diacetic acid, 1,3-phenylene diacetic acid, ammonium tartrate dibasic, potassium tartrate monobasic, ammonium hydrogen oxalate, monomethyl fumarate, and monoethyl fumarate; selected from the group consisting of derivatives of, and mixtures of.

In one embodiment, the polysiloxane is an amino-modified polysiloxane.

In certain embodiments, the amount of polysiloxane in the composition is about 50 to 95 weight percent, based on the total weight of the composition, such as about 60 to 80 weight percent, based on the total weight of the composition. be.

In certain embodiments, the emulsifier is nonionic. In some embodiments, the emulsifier is a water-soluble POE alkyl ether, POE alkylaryl ether, or POE fatty acid ester, or a mixture thereof.

In some embodiments, the amount of emulsifier in the composition is about 5 to 40 weight percent, particularly about 25 to 35 weight percent, based on the total weight of the composition.

Embodiments of the present invention are also directed to fibers comprising polyacrylonitrile and having a finishing coating of the present invention applied to the surface thereof.

Aspects of the invention are also directed to the use of finishing compositions for the manufacture of carbon fibers.

The invention has thus been described in general terms. Reference is now made to the accompanying drawings, which are not necessarily drawn to scale.

Figure 3 shows a schematic diagram of tow evaluation lines used to evaluate tow properties such as fuzz (number of damaged filaments).

The invention will be explained in more detail below with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. As used in this specification and the appended claims, the singular forms "a," "an," and "the" refer to plural referents unless the context clearly dictates otherwise. include.

I. definition

For the purposes of this application, the following terms shall have the following meanings:

The term "fiber" can refer to a finite length fiber or an infinite length filament.

The term "precursor fiber" refers to a fiber comprising a polymeric material that, upon application of sufficient heat, can be converted into a carbon fiber having a carbon content of about 85% by weight or greater, particularly about 95% by weight or greater. Precursor fibers can include both homopolymers and copolymers of acrylonitrile (AN), methyl acrylate (MA), methacrylic acid (MAA), sodium methallyl sulfonate, itaconic acid (IA), vinyl bromide. (VB), isobutyl methacrylate (IBMA), and combinations thereof. In one embodiment, the precursor fiber comprises a polyacrylonitrile (PAN) polymer formed primarily from acrylonitrile monomer.

As used herein, the terms "about" and "substantially" mean a deviation of less than 10%, especially less than 5%, less than 4%, less than 3%, and less than 2% from the stated value. (plus/minus).

Embodiments of the present invention are directed to emulsions that are particularly suitable for use as finishing compositions in the processing of PAN precursor fibers. In certain embodiments, the emulsion includes silicone oil, an emulsifier, water, and a dicarboxylic acid with a pKa of about 1 to 4 and a molecular weight of less than about 1,000 g/mole.

1. polysiloxane

Generally, a wide variety of different silicone oils may be used in embodiments of the present invention. Examples of such silicone oils generally include polysiloxanes such as polydimethylsiloxane, methylphenylpolysiloxane, poly(dimethylsiloxane-co-methylphenylsiloxane). Furthermore, polysiloxanes can be modified with epoxy or amino functional groups, among others.

In one embodiment, the silicone oil comprises an amino-modified polysiloxane. For example, the silicone oil may contain amino-modified siloxanes with a nitrogen content of 0.05 to 3.2% by weight, especially 0.05 to 2.0% by weight in the amino groups. Further discussion of polysiloxanes that may be used in embodiments of the present invention is discussed in US Pat. No. 5,726,241, the contents of which are incorporated herein by reference.

The structure of the amino-modified siloxane is not particularly limited to a specific structure. For example, in some embodiments, the amino group in the amino-modified siloxane, ie, the modifying group, can be attached to the main chain, ie, a side chain of the silicone, the end of the main chain, or both. The amino group can be either a monoamine or a polyamine, both of which can be present in one molecule of amino-modified siloxane.

In one embodiment, the silicone oil has the following formula;

an amino-modified polysiloxane having

In the formula, R ₂ is a hydrogen atom, a lower alkyl group or an aryl group, R ₃ and R ₄ are each a lower alkyl group or an aryl group, and R ₅ is a hydrogen atom or

is the basis of

In the formula, R ₈ and R ₉ are each a lower alkyl group, R ₁₀ is a hydrogen atom or a lower alkyl group, R ₆ and R ₇ are each a hydrogen atom or a lower alkyl group, and A is 2 to 5 carbon atoms or alkylene groups containing phenylene groups, and x and y are positive integers giving a molecular weight of the aminosiloxane of 100,000 or less.

In one embodiment, the aminosiloxane is a random copolymer consisting essentially of substituted siloxyl and aminosiloxyl repeat units, as shown in the general formula above, and liquid polymers having a molecular weight of 100,000 or less are generally used. Ru. The lower limit of such aminosiloxanes is generally about 2000, and the ratio (x:y) of substituted siloxyl units (x) to aminosiloxyl units (y) is preferably from 4 to 200:1. The lower alkyl groups selected as R ₂ , R ₃ , R ₅ , R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are generally lower alkyl groups having 1 to 6 carbon atoms, with 4 Preference is given to using lower alkyl groups having the following carbon atoms: Further discussion of such amino-modified polysiloxanes is found in US Pat. No. 4,009,248, the contents of which are incorporated herein by reference.

In further embodiments, the polysiloxane has the following formula:

an amino-modified polysiloxane having
where x is a number from 100 to 5,000, especially from 200 to 1,000, and y is a number from 1 to 100, especially from 5 to 50. In preferred embodiments, the x:y ratio is between about 10 and 1,000, particularly between about 10 and 400.

In certain embodiments, the polysiloxane has the following formula:

an amino-modified polysiloxane having
In the formula, R ₁₂ is a C1-20 alkyl or aryl group, preferably a C1-10 alkyl or aryl group, more preferably a C1-5 alkyl group, even more preferably a methyl group. A plurality of R ₁₂ 's in the formula may be the same or different. _R13 has the following chemical formula:

It is a group represented by

R ₁₁ is a group represented by R ₁₂ , R ₁₃ , or --OR ₁₀ , and preferably R ₁₂ . A plurality of R _11s may be the same or different. R ₁₀ is a hydrogen atom or a C _1-6 alkyl group, preferably a hydrogen atom or a C _1-4 alkyl group, more preferably a hydrogen atom or a methyl group, and p is 10 to 10,000, preferably 50 to _5,000 . , more preferably a number in the range of 100 to 2000, and q is a number in the range of 0.1 to 1000, preferably 0.5 to 500, more preferably 1 to 100.

In the above formula, each of R ₁₄ and R ₁₆ is independently a C ₁ -C ₆ alkylene group, preferably a C ₁ -C ₃ alkylene group. Each of R ₁₅ , R ₁₇ and R ₁₈ is independently a hydrogen atom or a C ₁ -C ₁₀ alkyl group or an aryl group, preferably a hydrogen atom or a C ₁ -C ₅ alkyl group, more preferably a hydrogen atom. , r is a number ranging from 0 to 6, preferably from 0 to 3, more preferably from 0 to 1.

Other polysiloxanes that may be used in certain embodiments of the invention include:

where x is a number from 100 to 5,000, especially from 200 to 1,000, and y is a number from 1 to 100, especially from 10 to 50.

where x is a number from 100 to 5,000, especially from 200 to 1,000, and y is a number from 10 to 500, especially from 10 to 100.

where x is a number from 10 to 5,000, especially from 50 to 1,000, y is a number from 1 to 100, especially from 10 to 50, and n is a number from 1 to 100, especially from 5 to 50. be.

The viscosity of the polysiloxane at 25°C is not particularly limited, but if the viscosity of the polysiloxane is too low, the resulting finishing composition may easily fall off from the fibers, or the stability of the aqueous emulsion of the resulting finishing composition may be affected. resulting in uneven application of the finish to the fibers and failure to prevent fiber fusing. On the other hand, if the viscosity of the polysiloxane is too high, it may become sticky and the silicone may become gummy. In some embodiments, the viscosity of the polysiloxane at 25° C. is between 100 and 100,000 cps, particularly between 100 and 15,000 cps, more specifically between 500 and 10,000 cps, and even more specifically between 1,000 cps and 1,000 cps. A range of ˜5,000 cps may be desirable.

In some embodiments, silicone oil may include a mixture of different polysiloxanes. For example, in certain embodiments, silicone oils may include amine-modified polysiloxanes in combination with one or more of polydimethylsiloxanes or polymethylphenylsiloxanes, or polyether-modified or epoxy-modified or other modified polysiloxanes.

The amount of silicone oil in the finishing composition typically ranges from about 50 to 95 weight percent based on the total weight of the finishing composition, more specifically from about 65 to 90 weight percent based on the total weight of the finishing composition. Typically, it is about 60 to 80 percent by weight.

Desirably, polysiloxanes such as amino-modified polysiloxanes should be incorporated into the PAN precursor fibers in an amount of at least 0.01%, preferably at least 0.05%, based on the weight of the PAN precursor fibers. . When the amount introduced is less than 0.01%, it is difficult to fully exhibit the effects of the present invention. On the other hand, introducing excessive amounts of polysiloxane is not economical since no better effect is expected. Therefore, the upper limit of the amount of aminosiloxane introduced is preferably about 5% based on the weight of the PAN precursor fiber.

2. dicarboxylic acid

As previously mentioned, improved stability, heat resistance, and heat resistance can be achieved by including in the finishing composition a dicarboxylic acid with a pKa of about 1 to 4, a molecular weight of less than 1,000 g/mol, and a boiling/decomposition point of 200 to 400°C. It has been found that emulsions having a carbon fiber fuzz and filament damage are provided which result in less carbon fiber fuzz and reduced filament damage.

In one embodiment, the dicarboxylic acid has the formula:

has
where R ₁ is absent or a saturated or unsaturated, straight-chain or branched, aromatic, substituted or unsubstituted hydrocarbon group,
Y ₁ and Y ₂ are independently nitrogen, oxygen, sulfur or phosphorus-containing groups, hydrogen, C ₁ -C ₆ alkyl groups, alkoxy groups, and/or phenyl groups.
X ₁ and X ₂ are independently hydrogen, a metal, a quaternary amine, an alcohol, or a hydrocarbon group having up to 6 carbon atoms, where the hydrocarbon group is an alkyl group, an alkylene group, or an aromatic group. group groups, which may be branched or straight chained and optionally have one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus.

Examples of metals for X ₁ and X ₂ include alkali metals such as lithium, potassium, and sodium.

Generally, R ₁ is not limited to a particular chain length or moiety, so long as the pK _a1 of the dicarboxylic acid is about 4 or less. For example, if R ₁ is a saturated straight alkyl chain, the number of carbon atoms will generally be 4 or less. However, if R ₁ contains additional moieties such as nitrogen, oxygen, sulfur or phosphorus-containing groups, aromatic groups, alkenes or alkynes, then _{R 1} The number of carbon atoms (if any) can be increased.

As guidance, some examples of possible embodiments of R ₁ are provided below, where R ₁ is:

saturated branched alkyl chains with up to 4 carbon atoms,

a saturated straight alkyl chain having 2 to 3 carbon atoms;

Saturated straight or branched alkyl chains substituted with one or more nitrogen-, oxygen-, sulfur- or phosphorus-containing groups (examples of such substituents include carbonyls, ethers, amides, amines, alcohols, etc.) ,

unsaturated branched or straight-chain alkyl groups having up to 6 carbon atoms,

an unsaturated branched or straight-chain alkyl group substituted with one or more nitrogen-, oxygen-, sulfur- or phosphorus-containing groups, the number of carbon atoms in the straight alkyl chain being up to 6 (for such groups Examples include carbonyls, ethers, amides, amines, alcohols, etc.),

one or more polyethylene glycol or polypropylene glycol groups,

Aromatic groups optionally substituted with one or more of alkyl groups having 1 to 6 carbon atoms, nitrogen-containing groups, oxygen-containing groups, sulfur-containing groups, or phosphorus-containing groups (such substitutions Examples of groups include carbonyl, ether, amide, amine, alcohol, etc.), and

selected from hydrocarbons having one or more of the following: alkene, alkyne, alcohol, carbonyl, ether, amine, amide, phenyl, benzene, furan, pyridine, or pyran group, or imidazole group.

In some embodiments, R ₁ can also include combinations of the aforementioned exemplary hydrocarbon groups. It should also be recognized that in some embodiments R ₁ may be absent.

Typically, the pK _a1 of the dicarboxylic acid is about 1 to 4, especially about 2 to 3.5.

In addition to limiting the pK _a1 of the dicarboxylic acid, it is also desirable for the dicarboxylic acid to have a molecular weight of about 50 to 1,000 g/mol, particularly about 75 to 500, and more specifically about 100 to 250 g/mol.

In one embodiment, the dicarboxylic acid is less than 1,000 g/mol, less than 950 g/mol, less than 900 g/mol, less than 850 g/mol, less than 800 g/mol, less than 750 g/mol, less than 700 g/mol, less than 650 g/mol. , less than 600 g/mol, less than 550 g/mol, less than 500 g/mol, less than 450 g/mol, less than 400 g/mol, less than 350 g/mol, 300 g/mol, less than 250 g/mol, less than 200 g/mol, less than 150 g/mol, and a molecular weight of less than 100 g/mol.

In one embodiment, the dicarboxylic acid is greater than 50 g/mol, greater than 100 g/mol, greater than 150 g/mol, greater than 200 g/mol, greater than 250 g/mol, greater than 300 g/mol, greater than 350 g/mol. , more than 400 g/mol, more than 450 g/mol, more than 500 g/mol, less than 550 g/mol, more than 600 g/mol, less than 650 g/mol, more than 700 g/mol, 750 g/mol, more than 800 g/mol , greater than 850 g/mol, greater than 900 g/mol, and greater than 950 g/mol.

In certain embodiments, the dicarboxylic acid has a boiling point of about 200-400°C. For example, the boiling point/decomposition temperature of the dicarboxylic acid may be about 225-375°C, particularly about 250-350°C, more specifically about 275-350°C. Preferably, the boiling point/decomposition temperature of the dicarboxylic acid is below 350°C but above 200°C.

The amount of dicarboxylic acid present in the finishing composition may range from about 0.1 to 10 weight percent, based on the total weight of the composition, more specifically from about 0.5 to 10 percent, based on the total weight of the composition. Typically, it may range from about 1 to 10 weight percent. In some embodiments, the amount of dicarboxylic acid present in the finishing composition is about 1 to 8 weight percent, particularly about 2 to 6 weight percent, and more specifically about 3 to 5 weight percent.

Examples of dicarboxylic acids that may be used in certain embodiments of the invention include DL-tartaric acid, L-tartaric acid, D-tartaric acid, fumaric acid, mesaconic acid, oxamic acid, succinic acid, 2-methylsuccinic acid, L-malic acid. Acid, DL-malic acid, D-malic acid, aspartic acid, mesooxalic acid, muconic acid, oxaloacetic acid, glutamic acid, diglycolic acid, iminodiacetic acid, 2,2'-oxydipropanoic acid, 3,3'-oxy Dipropanoic acid, 2,2'-[1,2-ethanediylbis(oxy)]bis-acetic acid, 3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid, 3,3'-[oxybis (ethane-2,1-diyloxy)] dipropanoic acid, poly(ethylene glycol) bis-acetic acid, polyethylene glycol bis(carboxymethyl) ether, polyethylene glycol dioic acid 600, chelidonic acid, dipicolinic acid, 2,5-furandicarboxylic acid , isophthalic acid, terephthalic acid, orthophthalic acid, trimesic acid, 1,4-phenylene diacetic acid, 1,3-phenylene diacetic acid and their derivatives, such as ammonium tartrate dibasic, potassium tartrate monobasic, hydrogen oxalate Includes ammonium, monomethyl fumarate, monoethyl fumarate, and mixtures thereof.

In some embodiments, the dicarboxylic acids include the following hydroxypyruvic acid, alpha-ketoglutaric acid and beta-ketoglutaric acid, alpha-ketoadipic acid, alpha-ketovaleric acid, levulinic acid, 4-hydroxy-2-oxopentanoic acid. , and 4-hydroxyphenylpyruvic acid.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

according to one of the following: oxamic acid or oxamine derivatives.

In oxamic acid, R ₁ is absent, X ₁ Y ₁ is an amine, and X ₂ Y ₂ is an OH group. Oxamic acid has a pK _a1 of 2.49 and a molecular weight of 89.05 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

according to one of the above, including keto acids such as α-ketovaleric acid or its derivatives.

In ketovaleric acid, R ₁ is not present, one of X ₁ Y ₁ and X ₂ Y ₂ is a propyl group, and the other is an OH group. In the second structure above, the keto acid is α-ketoisovaleric acid with a pK _a1 of 3.37.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

4-hydroxy-2-oxopentanoic acid, or a derivative thereof.

In 4-hydroxy-2-oxopentanoic acid, R ₁ is absent, one of X ₁ Y ₁ and X ₂ Y ₂ is propyl alcohol, and the other is an OH group. The molecular weight of 4-hydroxy-2-oxopentanoic acid is 132.11 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

4-hydroxyphenylpyruvate, or a derivative thereof.

In 4-hydroxyphenylpyruvic acid, R ₁ is not present, one of X ₁ Y ₁ and X ₂ Y ₂ is methylphenol, and the other is an OH group. The melting point of 4-hydroxyphenylpyruvic acid is 219°C, and the pK _a1 is 2.98.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

hydroxypyruvic acid or a derivative thereof.

In hydroxypyruvic acid, R ₁ is absent, X ₁ Y ₁ is an OH group, and X ₂ Y ₂ is methyl alcohol. Hydroxypyruvic acid has a boiling point of 257°C, a pK _a1 of 2.57, and a molecular weight of 104.06 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

oxaloacetic acid or oxaloacetic acid derivatives.

In this embodiment, R ₁ includes a carbonyl group and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. Oxaloacetic acid has a pK _a1 of 2.22 and a boiling point of 217°C.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, it includes tartaric acid or tartaric acid derivatives.

In this embodiment, R ₁ contains two alcohols (OH groups) and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. DL-tartaric acid has a boiling point of 273°C and a pK _a1 of 3.22.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, fumaric acid or fumaric acid derivatives are included.

In fumaric acid, R ₁ is an ethylene group and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. The decomposition temperature of fumaric acid is 287°C, and the pK _a1 is 3.03.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, it includes mesaconic acid or mesaconic acid derivatives.

The decomposition temperature of mesaconic acid is 250°C, and the pK _a1 is 3.72.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

succinic acid or succinic acid derivatives.

Succinic acid has a boiling point of 235°C and a pK _a1 of 4.2.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

contains malic acid or malic acid derivatives.

In malic acid, R ₁ contains an OH group. The decomposition temperature of malic acid is 225°C, and the pK _a1 is 3.4.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

aspartic acid or aspartic acid derivatives.

In this embodiment, R ₁ comprises an amine group and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. The decomposition temperature of aspartic acid is 324°C, and the pK _a1 is 3.9.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, it contains mesooxalic acid or mesooxalate derivatives.

In this embodiment, R ₁ includes a carbonyl group and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. The pK _a1 of mesooxalic acid is 1.23.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

Muconic acid or muconic acid derivatives.

The decomposition temperature of muconic acid is 345°C, and the pK _a1 is 3.87.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

glutamic acid or glutamic acid derivatives.

The pK _a1 of glutamic acid is 2.19.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, diglycolic acid or diglycolic acid derivatives are included.

In this embodiment, R ₁ comprises an ether and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

iminodiacetic acid or iminodiacetic acid derivatives.

In iminodiacetic acid, R ₁ includes an amide and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. Iminodiacetic acid has a pK _a of 1.873, a boiling point of 371° C., and a molecular weight of 133.1 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

oxydipropanoic acid or oxydipropanoic acid derivatives (eg, 2,2'-oxydipropanoic acid and 3,3'-oxydipropanoic acid).

In oxydipropanoic acid, R ₁ contains an ether group and X ₁ Y ₁ and X ₂ Y ₂ are both OH groups. 2,2'-oxydipropanoic acid has a boiling point of 392° C. and a molecular weight of 162.14 g/mol. The boiling point of 3,3'-oxydipropanoic acid is 371.4°C and the molecular weight is 162.14 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

2,2'-[1,2-ethanediylbis(oxy)]bisacetic acid, or a derivative thereof.

The molecular weight of 2,2'-[1,2-ethanediylbis(oxy)]bisacetic acid is 178.14 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

3,3'-[1,2-ethanediylbis(oxy)]bispropanoic acid, or a derivative thereof.

The molecular weight of 3,3'-[1,2-ethanediylbis(oxy)]bispropanoic acid is 206.19 g/mol.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

Accordingly, potassium tartrate monobasic or its derivatives are included.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

ammonium tartrate dibasic or derivatives thereof.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

chelidonic acid or its derivatives.

The decomposition temperature of chelidonic acid is 257°C, and the pK _a1 is 1.7.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

According to the above, it includes dipicolinic acid or its derivatives.

The decomposition temperature of dipicolinic acid is 248°C, and the pK _a1 is 3.24.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

Accordingly, it includes furan derivatives such as 2,5-furandicarboxylic acid or its derivatives.

The pK _a1 of 2,5-furandicarboxylic acid is 2.28.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

1,3-phenylenediacetic acid or 1,4-phenylenediacetic acid or derivatives thereof.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

Accordingly, phthalic acid or phthalic acid derivatives, such as orthophthalic acid, isophthalic acid, terephthalic acid, and trimesic acid, or derivatives thereof.

In one embodiment, the dicarboxylic acid has the following exemplary formula:

Accordingly, fumaric acid derivatives such as monomethyl fumarate or monoethyl fumarate are included.

3. emulsifier

The finishing composition may also include emulsifiers. Generally, emulsifiers are surfactants used to emulsify or disperse the polysiloxanes described above in water. The emulsifier is not particularly limited and can be selected from nonionic, anionic, cationic and amphoteric surfactants known to those skilled in the art. One or a combination of at least two such emulsifiers can be used.

Specific examples of nonionic emulsifiers include linear polyoxyalkylene alkyl ethers, such as polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, and polyoxyethylene cetyl ether. Ethers; branched polyoxyalkylene primary alkyl ethers, such as polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isocetyl ether and polyoxyethylene isostearyl ether; branched polyoxyalkylene secondary alkyl ethers, such as: Polyoxyethylene 1-hexylhexyl ether, polyoxyethylene 1-octylhexyl ether, polyoxyethylene 1-hexyl octyl ether, polyoxyethylene 1-pentylheptyl ether and polyoxyethylene 1-heptylpentyl ether; polyoxyalkylene alkenyl ether , such as polyoxyethylene oleyl ether; polyoxyalkylene alkylphenyl ethers, such as polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether and polyoxyethylene dodecylphenyl ether; polyoxyalkylene alkylaryl phenyl ether, such as polyoxyethylene Oxyethylene tribenzylphenyl, polyoxyethylene dibenzylphenyl ether and polyoxyethylene benzylphenyl ether; polyoxyalkylene fatty acid esters, such as polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene monostearate, Polyoxyethylene myristate, polyoxyethylene dilaurate, polyoxyethylene dioleate, polyoxyethylene dimyristate and polyoxyethylene distearate; sorbitan esters, such as sorbitan monopalmitate and sorbitan monooleate; polyoxyalkylene sorbitan Fatty acid esters, such as polyoxyethylene sorbitan monostearate and polyoxyethylene sorbitan monooleate; glycerin fatty acid esters, such as glycerin monostearate, glycerin monolaurate and glycerin monopalmitate; polyoxyalkylene sorbitol fatty acid esters; sucrose fatty acids Esters; polyoxyalkylene castor oil ethers, e.g. polyoxyethylene castor oil ether; polyoxyalkylene hydrogenated castor oil ethers, e.g. polyoxyethylene hydrogenated castor oil ether; polyoxyalkylene alkylamino ethers, e.g. polyoxyethylene lauryl amino ethers and polyoxyethylene stearyl amino ethers; oxyethylene-oxypropylene block or random copolymers; terminal alkyl etherified oxyethylene-oxypropylene block or random copolymers; and terminal sucrose-etherified oxyethylene-oxypropylene block or random copolymers Copolymers may be mentioned.

Among these nonionic emulsifiers, branched polyoxyalkylene primary alkyl ether, branched polyoxyalkylene secondary alkyl ether, polyoxyalkylene alkenyl ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene fatty acid ester, Oxyethylene-oxypropylene block copolymers and terminally alkyl etherified oxyethylene-oxypropylene block copolymers are preferred for their superior ability to emulsify silicone compounds in water. Additionally, oxyethylene-oxypropylene block or random copolymers and terminally alkyl etherified oxyethylene-oxypropylene block copolymers due to their ability to transform into tar-like substances on the fibers during the firing process to protect the fibers from damage. more preferred.

As anionic emulsifiers, salts of various acids, such as salts of fatty acids; salts of hydroxyl-containing carboxylic acids, such as hydroxyacetic acid, potassium hydroxyacetate, lactic acid and potassium lactate; salts of polyoxyalkylene alkyl ether acetic acids, e.g. , polyoxyalkylene tridecyl ether acetic acid sodium salt; salts of carboxyl polysubstituted aromatic compounds, such as potassium trimellitate and potassium pyromellitate; salts of alkylbenzenesulfonic acids, such as dodecylbenzenesulfonic acid; polyoxyalkylene alkyl Salts of ether sulfonic acids, such as polyoxyethylene 2-ethylhexyl ether sulfonic acids; salts of higher fatty acid amide sulfonic acids, such as stearoylmethyltaurine salts, lauroylmethyltaurine salts, myristoylmethyltaurine salts and palmitoylmethyl Salts of taurine; salts of N-acyl sarcosinates, for example salts of lauroyl sarcosinate; salts of alkylphosphonic acids, for example salts of octyl phosphonate; salts of aromatic phosphonic acids, for example potassium salts of phenyl phosphonate; Salts of alkylphosphonic acids, such as the salts of 2-ethylhexylphosphonate mono-2-ethylhexyl ester; salts of nitrogen-containing alkylphosphonic acids, such as the salts of aminoethylphosphonic acid and its diethanolamine salts; salts of alkyl sulfates , for example salts of 2-ethylhexyl sulfate; salts of polyoxyalkylene sulfates, eg salts of polyoxyethylene 2-ethylhexyl ether sulfate; salts of long chain sulfosuccinates, eg salts of di-2-ethylhexyl sodium sulfosuccinate. and dioctyl sodium sulfosuccinate; and long chain N-acyl glutamates, such as monosodium N-lauroylglutamate and disodium N-stearoyl-L-glutamate.

Cationic emulsifiers include, in particular, quaternary ammonium salts, such as lauryl trimethyl ammonium chloride and ammonium oleyl methyl ethyl ethosulfate; and (polyoxyalkylene) alkylamino ether salts, such as (polyoxyethylene) lauryl amino ether. Examples include lactate, stearyl aminoether lactate, and (polyoxyethylene) lauryl aminoether trimethyl phosphate salt.

Amphoteric emulsifiers include imidazoline amphoteric surfactants, such as sodium 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazophosphate and 2-cocoyl-2-imidazolinium hydroxide. -1-carboxyethyloxyacid disodium; betaine amphoteric surfactants, such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, lauryldimethylaminoacetic acid betaine, alkylbetaine, amidobetaine and sulfobetaine; Also included are amino acid amphoteric surfactants such as N-laurylglycine, N-lauryl-β-alanine and N-stearyl-β-alanine.

Among the emulsifiers mentioned above, ionic surfactants can change over time in the emulsion of the precursor finish and can affect the crosslinking performance of the silicone. Nonionic emulsifiers are therefore preferred in finishing compositions because of their stability throughout storage, minimal impact on silicone crosslinking performance, and superior ability to emulsify silicone.

Preferred emulsifiers are further described in US Pat. No. 5,726,241. In particular, preferred emulsifiers may include non-ionic emulsifiers such as water-soluble POE alkyl ethers, POE alkylaryl ethers or POE fatty acid esters, or mixtures thereof. The weight proportion of emulsifier in the finishing composition of the invention should preferably range from 1 to 40% by weight, more preferably from 5 to 30% by weight, even more preferably from 8 to 25% by weight.

In one embodiment, the amount of emulsifier is about 5 to 40 weight percent, based on the total weight of the composition, particularly about 20 to 40 weight percent, more specifically about 25 weight percent, based on the total weight of the composition. ~35 weight percent.

4. monocarboxylic acid

In some embodiments, the finishing composition may also include a weakly acidic species, such as a monocarboxylic acid with a pK _a1 greater than about 3.7, eg, a pK _a1 of 3.77 to 4.88. Such monocarboxylic acids are described in further detail in US Pat. No. 5,726,241. In one embodiment, the monocarboxylic acids include lower aliphatic monocarboxylic acids having 6 or fewer carbon atoms. In the '247 patent, monocarboxylic acids can be added to promote emulsification of the polysiloxane. Examples of monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, etc., or hydroxycarboxylic acids with up to 4 carbon atoms, such as glycolic acid, lactic acid, etc. is included. These monocarboxylic acids can be used alone or as a mixture of two or more thereof.

5. viscosity modifier

In some embodiments, the finishing composition may include one or more viscosity modifiers. Generally, viscosity modifiers include any composition that desirably alters viscosity without interfering with the effects of the present invention. In some embodiments, viscosity modifiers can include aminocarboxylic acid materials such as alkylamine carboxylates, arylamine carboxylates, alkylarylamine carboxylates, amino acids, and betaine compounds. In preferred embodiments, the viscosity modifier comprises β-alanine or 2-(dibutylamino)ethanol acetate.

When present, the amount of viscosity modifier is about 0.1 to 10 weight percent, particularly about 0.5 to 8 weight percent, more specifically about 1 to 8 weight percent, based on the total weight of the finishing composition. It is a percentage.

6. additional ingredients

In addition to the above-mentioned ingredients, the finishing composition of the present invention may contain further ingredients as long as those ingredients do not interfere with the effects of the present invention. These ingredients include antioxidants, such as phenolic compounds, amine compounds, sulfur compounds, phosphorus compounds or quinone compounds; antistatic agents, such as sulfates, sulfonates of higher alcohols or higher alcohol ethers, higher alcohols or Cationic surfactants of phosphates of higher alcohol ethers, quaternary ammonium salts, and amine salts; Lubricants, such as alkyl esters of higher alcohols, ethers of higher alcohols, and waxes; Antibacterial agents agents; preservatives; rust inhibitors; and hygroscopic agents.

example

tensile strength

The tensile strength of carbon fiber samples was measured according to the procedure described in ASTM D-4018.

viscosity

All viscosity measurements were performed on emulsions containing 20% solids at 20° C. on a DV-I Prime viscometer (Brookfield) equipped with a thermostatic water bath.

pH

All pH readings of the emulsions were taken on an ab Accumet Basic pH meter (Fischer Scientific) equipped with a temperature compensated probe.

Turbidity

The turbidity of the 20% solids emulsion was measured with a Hach 2100AN turbidimeter (Hach USA) and reported in NTU.

Tow characterization

Following carbonization, the fuzz (number of damaged filaments) of the carbon fibers was evaluated. This evaluation was performed using the tow evaluation line shown schematically in FIG.

Fluff: The number of damaged filaments (fluff 1 and fluff 2) was analyzed by laser shielding. A tape corresponding to the width of the tow was placed along the path of the tow on detector "LX2-12" and nitrogen was blown upward at a rate of 30 cfph just in front of the detector perpendicular to the fiber path. The detector "LX2-12" was connected to amplifiers "LX2-70" and "PG-610", and the amplifiers were connected to the "RC-2" counter (all manufactured by Keyence).

All results are based on 250 feet of fiber processed on a tow evaluation line operating at 800 feet/hour. Measurements were taken every 3 seconds.

Measuring aminosiloxane finishing oil content

Samples of PAN precursor fibers treated with the finishing composition were alkaline fused with potassium hydroxide/sodium butyrate, then dissolved in water and adjusted to pH 1 with hydrochloric acid. Sodium sulfite and ammonium molybdate were added to this to develop a color, and color measurement was performed using silica molybdenum blue (wavelength: 815 mμ) to measure the silicon content. Using this silicon content value and the silicon content of the crude aminopolysiloxane previously determined in the same manner, the polysiloxane content of the sample was calculated.

The materials used in the finishing composition are shown below. All percentages are by weight unless otherwise specified. Unless otherwise specified, all physical properties and compositional values are approximate.

"Emulsifier" refers to ethoxylated tridecyl alcohol available from Ethox under the product name ETHAL® TDA-9.

Acetic acid (ACS reagent grade ≧99%) was obtained from Sigma-Aldrich.

Oxamic acid (98%) was obtained from Acros Organics.

Humic acid (99%) was obtained from Sigma-Aldrich.

D,L-tartaric acid (DL-2,3-dihydroxybutanedioic acid) (≧99%) was obtained from Sigma-Aldrich.

β-Alanine (99%) was obtained from Sigma-Aldrich and was used as a viscosity modifier.

2-(Dibutylamino)ethanol (99%) was obtained from Sigma-Aldrich. It was reacted with an equimolar amount of acetic acid and the product obtained was used as a thinning agent.

The polysiloxane used in the example was an amine modified polysiloxane with a viscosity of 2100 cps and an amine content of 14 mg KOH/g. Polysiloxane has the following structure:

It had

The properties of the acids used in the examples are summarized in Table 1 below.

The following examples utilized two different methods of preparing emulsions, as described below.

Emulsification Procedure A: Silicone oil was pre-reacted with organic acid with stirring for 2 hours at ambient temperature. The aqueous solution of emulsifier and any additional additives was then mixed with the silicone oil mixture at a temperature of 60°C. The combined mixture was mixed under high shear for 1 hour at a temperature of 58°C.

Emulsification procedure B: The aqueous solution of emulsifier, any additives and organic acid were introduced into the mixer at a temperature of 60°C. Silicone oil was then slowly added to the mixture at 58° C. for 1 hour under higher shear.

The emulsion composition was prepared in a PVM-2 mixer (Charles Ross & Son Co.) equipped with temperature control.

Comparative example 1

Comparative Example 1 was prepared according to the teachings of US Pat. No. 5,726,241. The finishing composition of Comparative Example 1 was prepared by adding 3 parts of β-alanine to 102 parts of a 66/33/3 mixture of polyaminosiloxane/Ethal TDA-9 (C13EO10)/acetic acid. An aqueous emulsion with a solids content of 20% by weight was prepared using emulsification procedure A above.

The finishing composition of Comparative Example 1 also served as the base formulation for Examples 1-5 in which the dicarboxylic acid was added at ambient temperature and stirred magnetically until dissolved.

Invention example 1

5 parts of DL-tartaric acid was dissolved in the emulsion of Comparative Example 1.

Invention example 2

In Inventive Example 2, 3 parts of fumaric acid was dissolved in the emulsion of Comparative Example 1.

Invention example 3

In Inventive Example 4, 2 parts of oxamic acid was dissolved in the emulsion of Comparative Example 1.

Invention example 4

In Inventive Example 4, 3 parts of oxamic acid replaced acetic acid in the formulation of Comparative Example 1. Additionally, emulsions were prepared using Emulsification Procedure B above.

Comparative example 2

Again, the emulsion composition of Comparative Example 2 was based on the emulsion composition described in US Pat. No. 5,726,241. Comparative Example 2 served as both a control and a stock composition for preparing the emulsions of Examples 5-6. In Examples 5-8, dicarboxylic acids were added to the formulations under ambient conditions and stirred magnetically until dissolved. The emulsion of Comparative Example 2 was prepared by adding 4.5 parts of dibutylethanolamine acetate to 102 parts of a 66/33/3 mixture of polyaminosiloxane/Ethal TDA-9 (C13EO10) as emulsifier/acetic acid. An aqueous emulsion with a solids content of 20% by weight was prepared using emulsification procedure A above.

Invention example 5

Inventive Example 5 was prepared by dissolving 3 parts of fumaric acid in the emulsion composition of Comparative Example 2.

Invention example 6

Inventive Example 6 was prepared by dissolving 2 parts of oxamic acid in the emulsion composition of Comparative Example 2.

Invention example 7

In Inventive Example 7, 3 parts of oxamic acid completely replaced 2 parts of acetic acid in the emulsion composition described in Comparative Example 2. Additionally, emulsions were prepared using Emulsification Procedure B above.

Comparative example 3

Again, the emulsion composition of Comparative Example 3 was based on the emulsion composition described in US Pat. No. 5,726,241. Comparative Example 3 served as both a control and a stock composition for preparing the emulsions of Examples 8-9. In Examples 8-9, the dicarboxylic acid was added to the formulation under ambient conditions and stirred magnetically until dissolved. In the emulsion of Comparative Example 3, 4.5 parts of dibutylethanolamine acetate was mixed with polyaminosiloxane/Ethal TDA-9 (C13EO10) as an emulsifier/acetic acid/AO-26 antioxidant (ADEKA Co., Ltd.) 66/33/ Prepared by adding to 104 parts of the 3/2 mixture. An aqueous emulsion with a solids content of 20% by weight was prepared using emulsification procedure A above.

Invention example 8

Inventive Example 8 was prepared by dissolving 3 parts of fumaric acid in the emulsion composition of Comparative Example 3.

Invention example 9

Inventive Example 9 was prepared by dissolving 3 parts of L-aspartic acid in the emulsion composition of Comparative Example 3.

Invention example 10

In Invention Example 10, 2.2 parts of L-aspartic acid completely replaced 3 parts of acetic acid in the emulsion composition described in Comparative Example 3. Additionally, emulsions were prepared using Emulsification Procedure B above.

Next, the characteristics of the emulsions of Comparative Examples 1 to 3 and Invention Examples 1 to 10 were evaluated. The results are summarized in Table 2 below.

Next, the performance of the emulsions of Comparative Examples 1-3 and Inventive Examples was evaluated during the carbonization process. A tow of PAN precursor fibers was coated with an emulsion and then passed through an oxidation and carbonization furnace to produce carbon fibers, as described below. The process of preparing PAN precursor fibers is discussed below.

The polyacrylonitrile (PAN) precursor fibers used in the examples were prepared as follows. Fibers were made from a copolymer containing 98 mole % acrylonitrile and 2% methacrylic acid by air-gap wet spinning. A single tow pilot spinning line was adopted. The spinning and coagulant solution was based on an aqueous sodium thiocyanate solution. The fibers were stretched during spinning compared to their length after extrusion from the spinneret.

The precursor fibers were bundled into tows of 3,000 (3K) filaments per tow, and the filament denier was 1.3 dpf. The tow was then passed through a bath containing a 5.5% by weight aqueous emulsion of the finishing composition described above (Comparative Examples 1-2 and Inventive Examples 1-7), where the finishing composition was applied by a dipping kiss roll. The fibers were then dried on drying rolls to contain about 1% by weight of the finishing composition.

In Examples 1-4 and Comparative Example 1, a 1.5 kg (fiber weight) spool of 3K precursor fiber was converted to carbon fiber by Hexcel's proprietary procedure on a pilot carbon fiber line. The resulting fiber tow was not surface treated. In the final step, all fibers were sized with Hexcel's proprietary G sizing agent. The amount of sizing agent for all fibers was 1% by weight. The fibers were then subjected to tensile testing and tow characterization.

In Examples 5-10 and Comparative Examples 2-3, 20 kg (fiber weight) spools of 3K precursor fiber were converted to carbon fiber by Hexcel's proprietary procedures on the production line. The obtained fiber tow was surface treated. In the final step, all fibers were sized with Hexcel's proprietary G sizing agent. The amount of sizing agent for all fibers was 1% by weight. The results are summarized in Table 3.

From Table 3, it can be seen that the measured tensile strength of carbon fibers did not vary significantly between the comparative and inventive examples, but the difference between the measured fuzz and damaged filaments was quite large. . In particular, Inventive Examples 1 to 5 showed an average value of fluff 1 of 9, compared to Comparative Example 1, which had a fluff 1 value of 16. This is a 43.8% reduction in fluff 1. These results would be further improved if the results of Inventive Example 3 were not included, since the values of Inventive Example 3 appear to be outliers. In that case, the average of fluff 1 based on invention examples 1, 2, and 5 is 6, which is a 62.5% reduction in fluff 1. Regarding the value of fluff 2, the difference is even larger. The average value of fluff 2 in Invention Examples 1 to 4 is 4.75, compared to the value of fluff 2 in Comparative Example 1, which is 26. This is a difference of 81.7% in percentage. Regarding the comparison between Invention Examples 5 to 7 and Comparative Example 2, the difference in fluff values is even more remarkable.

Furthermore, the number of damaged filaments in the invention examples is also significantly improved compared to the comparative examples. The average number of damaged filaments in Invention Examples 1 to 4 was 13.8, but the number of damaged filaments in Comparative Example 1 was 42, and as a result, the number of damaged filaments was reduced by 67.1%. Regarding the comparison between Invention Examples 5 to 7 and Comparative Example 2, the difference in the number of damaged filaments is even more remarkable.

In Inventive Examples 8 to 10, it can be seen that the finishing composition of the present invention provides an improvement in the number of damaged filaments and fuzz compared to Comparative Example 3, which does not contain dicarboxylic acid. Although not as pronounced as in the previous example, the improvement in fiber performance is still significant.

Therefore, by including a dicarboxylic acid with a molecular weight less than 1,000 g/mol, a boiling/decomposition temperature of 200-400°C, and _a pKa less than 4, carbon fiber It can be seen that the performance has been significantly improved.
Aspects or embodiments that may be encompassed by the present invention are summarized as follows.
[1].
polysiloxane,
emulsifier,
water, and
Dicarboxylic acid with a pK _a of about 1 to 4 and a boiling point of 200 to 400°C
A finishing composition containing.
[2].
The finishing composition of item 1 above, further comprising a monocarboxylic acid having a pKa greater than 3.7 _.
[3].
The monocarboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, hydroxycarboxylic acids having up to 4 carbon atoms, such as glycolic acid and lactic acid. The finishing composition according to item 2 above.
[4].
The finishing composition according to any one or more of items 1 to 3 above, wherein the composition further comprises an aminocarboxylic acid material.
[5].
The finishing composition of item 4 above, wherein the aminocarboxylic acid material comprises β-alanine, 2-(dibutylamino)ethanol acetate, or a mixture thereof.
[6].
The finishing composition according to any one of items 1 to 5 above,
The dicarboxylic acid has the following formula:
[Chemical formula 1]

has
where R ₁ is absent or a saturated or unsaturated, straight-chain or branched, aromatic, substituted or unsubstituted hydrocarbon group,
Y ₁ and Y ₂ are independently nitrogen, oxygen, sulfur or phosphorus-containing groups, hydrogen, C ₁ -C ₆ alkyl groups, and/or alkoxy groups,
X ₁ and X ₂ are independently one or more hydrogen atoms, metals, quaternary amines, or hydrocarbon groups having up to 6 carbon atoms; or aromatic groups, which may be branched or straight-chained and optionally have one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus. good,
Finishing composition.
[7].
Finishing composition according to item 6 above, wherein R ₁ is a saturated straight alkyl chain having 2 to 3 carbon atoms.
[8].
Finishing composition according to item 6 above, wherein R ₁ is a saturated branched alkyl chain having 2 to 4 carbon atoms.
[9].
According to item 6 above, R ₁ is a straight alkyl chain substituted with one or more nitrogen, oxygen, sulfur or phosphorous containing groups, and the number of carbon atoms in the straight alkyl chain is at most 6. finishing composition.
[10].
Finishing composition according to item 6 above, wherein R ₁ comprises one or more polyethylene or polypropylene glycol groups.
[11].
R ₁ is an aromatic group, optionally one or more of an alkyl group having 1 to 6 carbon atoms, a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, or a phosphorus-containing group Finishing composition according to item 6 above, which is a substituted aromatic group.
[12].
Any one of the above items 1 to 11, wherein R ₁ contains one or more of an alkene, alkyne, alcohol, carbonyl, ether, amine, amide, phenyl, benzene, furan, pyridine, pyran group, or imidazole group Finishing compositions as described in Section.
[13].
The finishing composition according to item 11 above, wherein R ₁ comprises a benzene group, a furan group, a pyridine group, or an imidazole group.
[14].
The finishing composition according to any one of items 6 to 13 above, wherein X ₁ and X ₂ are independently hydrogen, alcohol, or phenol.
[15].
Finishing composition according to any one of the above items 1 to 14, wherein the composition comprises a monocarboxylic acid with a pK a1 greater than 3.7, in particular greater than 4 _.
[16].
A finishing composition according to any one of items 1 to 15 above, wherein the dicarboxylic acid has a pK _a of about 2 to 3.5.
[17].
The finishing composition of any one of items 1-16 above, wherein the dicarboxylic acid has a pK _a of about 2-3.
[18].
Finishing composition according to any one of the above items 1 to 17, wherein the dicarboxylic acid has a molecular weight of about 100 to 600 g/mol.
[19].
Finishing composition according to any one of items 1 to 18 above, wherein the dicarboxylic acid has a molecular weight of about 125 to 250 g/mol.
[20].
Finishing composition according to any one of items 1 to 19 above, wherein the dicarboxylic acid has a boiling point/decomposition point of 200 to 450°C.
[21].
Finishing composition according to any one of items 1 to 20 above, wherein the dicarboxylic acid has a boiling point/decomposition point of about 200-350°C.
[22].
Finishing composition according to any one of items 6 to 21 above, wherein X ₁ Y ₁ and X ₂ Y ₂ are both OH groups.
[23].
Finishing composition according to any one of items 6 to 21 above, wherein X ₁ Y ₁ comprises an amine or amide group and X ₂ Y ₂ comprises an OH group.
[24].
Item 22 or 23 above, wherein R ₁ comprises one or more of an alkene, an alkyne, an alcohol, a carbonyl, an ether, an amine, an amide, a phenyl, a benzene, a furan, a pyridine, or a pyran group, or an imidazole group. Finishing composition.
[25].
The dicarboxylic acid is DL-tartaric acid, L-tartaric acid, D-tartaric acid, fumaric acid, mesaconic acid, oxamic acid, succinic acid, 2-methylsuccinic acid, L-malic acid, DL-malic acid, D-malic acid, asparagine. Acid, mesooxalic acid, muconic acid, oxaloacetic acid, glutamic acid, diglycolic acid, iminodiacetic acid, 2,2'-oxydipropanoic acid, 3,3'-oxydipropanoic acid, 2,2'-[1,2 -ethanediylbis(oxy)]bis-acetic acid, 3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid, 3,3'-[oxybis(ethane-2,1-diyloxy)]dipropanoic acid, Poly(ethylene glycol) bis-acetic acid, polyethylene glycol bis(carboxymethyl) ether, polyethylene glycol dioic acid 600, chelidonic acid, dipicolinic acid, 2,5-furandicarboxylic acid, isophthalic acid, terephthalic acid, orthophthalic acid, trimesic acid, From 1,4-phenylene diacetic acid, 1,3-phenylene diacetic acid, ammonium tartrate dibasic, potassium tartrate monobasic, ammonium hydrogen oxalate, monomethyl fumarate, and monoethyl fumarate, and derivatives and mixtures thereof. The finishing composition according to any one of items 1 to 24 above, selected from the group consisting of:
[26].
The dicarboxylic acid has the following exemplary formula:
[Chemical 2]

oxamic acid or oxamine derivative according to one of;
An example formula below:
[Chemical 3]

a keto acid such as α-ketovaleric acid or a derivative thereof;
An example formula below:
[C4]

4-hydroxy-2-oxopentanoic acid or a derivative thereof;
An example formula below:
[C5]

4-hydroxyphenylpyruvate or a derivative thereof according to one of the following;
An example formula below:
[Case 6]

hydroxypyruvic acid or a derivative thereof;
An example formula below:
[C7]

oxaloacetic acid or an oxaloacetic acid derivative according to one of the following;
An example formula below:
[Chem.8]

tartaric acid or tartaric acid derivatives;
An example formula below:
[Chem.9]

fumaric acid or fumaric acid derivatives;
An example formula below:
[Chemical formula 10]

mesaconic acid or mesaconic acid derivative;
An example formula below:
[Chemical formula 11]

succinic acid or a succinic acid derivative according to one of;
An example formula below:
[Chemical formula 12]

malic acid or malic acid derivatives;
An example formula below:
[Chem.13]

aspartic acid or aspartic acid derivatives;
An example formula below:
[Chem.14]

mesooxalic acid or mesooxalate derivatives;
An example formula below:
[Chem.15]

muconic acid or muconic acid derivatives;
An example formula below:
[Chem.16]

glutamic acid or glutamic acid derivative;
An example formula below:
[Chem.17]

diglycolic acid or diglycolic acid derivative;
An example formula below:
[Chem.18]

iminodiacetic acid or iminodiacetic acid derivatives;
An example formula below:
[Chem.19]

oxydipropanoic acid or oxydipropanoic acid derivatives (e.g. 2,2'-oxydipropanoic acid and 3,3'-oxydipropanoic acid);
An example formula below:
[C20]

2,2'-[1,2-ethanediylbis(oxy)]bisacetic acid or its derivatives;
An example formula below:
[chemical formula 21]

3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid or its derivatives;
An example formula below:
[Chem.22]

Potassium tartrate monobasic or derivatives thereof;
An example formula below:
[Chem.23]

tartaric acid dibasic or its derivatives;
An example formula below:
[C24]

chelidonic acid or its derivatives;
An example formula below:
[Chem.25]

dipicolinic acid or its derivatives;
An example formula below:
[C26]

Furan derivatives such as 2,5-furandicarboxylic acid or derivatives thereof;
An example formula below:
[C27]

1,3-phenylenediacetic acid or 1,4-phenylenediacetic acid, or derivatives thereof;
An example formula below:
[C28]

phthalic acid, or phthalic acid derivatives, such as orthophthalic acid, isophthalic acid, terephthalic acid, and trimesic acid, or derivatives thereof;
An example formula below:
[C29]

fumaric acid derivatives such as monomethyl fumarate or its monoethyl fumarate
The finishing composition according to any one of items 1 to 24 above, selected from the group consisting of:
[27].
Finishing composition according to any one of items 1 to 26 above, wherein the polysiloxane is an amino-modified polysiloxane.
[28].
The finishing composition of any one of items 1-27 above, wherein the amount of polysiloxane in the composition is about 50 to 95 weight percent, based on the total weight of the composition.
[29].
The finishing composition of any one of items 1-28 above, wherein the amount of dicarboxylic acid in the composition is about 60 to 80 weight percent, based on the total weight of the composition.
[30].
Finishing composition according to any one of items 1 to 29 above, wherein the emulsifier is non-ionic.
[31].
Finishing composition according to any one of items 1 to 30 above, wherein the emulsifier is a water-soluble POE alkyl ether, POE alkylaryl ether or POE fatty acid ester, or a mixture thereof.
[32].
A finishing composition according to any one of items 1 to 31 above, wherein the amount of emulsifier in the composition is about 25 to 35 weight percent, based on the total weight of the composition.
[33].
A fiber comprising polyacrylonitrile and having a finishing coating according to any one of items 1 to 32 above applied to the fiber surface.
[34].
Use of a finishing composition according to any one of the above items 1 to 32 for the production of carbon fibers.
[35].
Applying a finishing composition according to any one of items 1 to 32 above to polyacrylonitrile-based fibers to form a coating on the fibers.
A method of preparing treated fibers comprising:
[36].
36. The method of item 35 above, further comprising carbonizing the fibers to form carbon fibers.

Claims (30)

polysiloxane,
emulsifier,
A finishing composition comprising water and a dicarboxylic acid with a pKa _of 1 to 4 and a boiling point of 200 to 400°C ,
The dicarboxylic acid has the following formula:

(wherein R ₁ is absent or a saturated or unsaturated, linear or branched, aromatic, substituted or unsubstituted hydrocarbon group; R 1 is an amine group and an amide _group ; (excluding either);
The finishing composition further comprises an aminocarboxylic acid material.
Finishing composition . 2. The finishing composition of claim 1 further comprising a monocarboxylic acid _with a pK a greater than 3.7. 4. The monocarboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, and hydroxycarboxylic acids having up to 4 carbon atoms. Finishing composition according to 2. Finishing composition according to any one of claims 1 to 3, wherein the aminocarboxylic acid material comprises β-alanine, 2-(dibutylamino)ethanol acetate, or a mixture thereof. Finishing composition according to any one of claims 1 to 4 , wherein R ₁ is a saturated straight alkyl chain having 2 to 3 carbon atoms. Finishing composition according to any one of claims 1 to 4, wherein R ₁ is a saturated branched alkyl chain having 2 to 4 carbon atoms. Claims 1 to 4, wherein R ₁ is a straight alkyl chain substituted with one or more nitrogen, oxygen, sulfur or phosphorous containing groups, and the number of carbon atoms in the straight alkyl chain is at most 6. The finishing composition according to any one of the above . Finishing composition according to any one of claims 1 to 4 , wherein R ₁ comprises one or more polyethylene or polypropylene glycol groups . R ₁ is an aromatic group, optionally one or more of an alkyl group having 1 to 6 carbon atoms, a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, or a phosphorus-containing group Finishing composition according to any one of claims 1 to 4 , which is a substituted aromatic group. Any one of claims 1 to 9 , wherein R ₁ contains one or more of an alkene group , an alkyne group , an alcohol group, a carbonyl group , an ether group , a phenyl group , a benzene group , a furan group , or a pyran group . Finishing compositions as described in Section . 10. The finishing composition of claim 9 , wherein _R1 comprises a benzene group or a furan group . Finishing composition according to any one of the preceding claims , wherein the composition comprises a monocarboxylic acid with a pK _a1 greater than 3.7. Finishing composition according to any one of the preceding claims , wherein the dicarboxylic acid has a pK _a of 2 to 3.5. Finishing composition according to any one of claims 1 to 13 , wherein the dicarboxylic acid has a pK _a of 2 to 3. Finishing composition according to any one of the preceding claims , wherein the dicarboxylic acid has a molecular weight of 100 to 600 g/mol. Finishing composition according to any one of claims 1 to 15 , wherein the dicarboxylic acid has a molecular weight of 125 to 250 g/mol. Finishing composition according to any one of claims 1 to 16 , wherein the dicarboxylic acid has a boiling point/decomposition point of 200-450°C. Finishing composition according to any one of the preceding claims , wherein the dicarboxylic acid has a boiling point/decomposition point of 200-350 °C. The dicarboxylic acid is DL-tartaric acid, L-tartaric acid, D-tartaric acid, fumaric acid, mesaconic acid , succinic acid, 2-methylsuccinic acid, L-malic acid, DL-malic acid, D-malic acid , mesooxalic acid. , muconic acid, oxaloacetic acid , diglycolic acid , 2,2'-oxydipropanoic acid, 3,3'-oxydipropanoic acid, 2,2'-[1,2-ethanediylbis(oxy)]bis-acetic acid, 3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid, 3,3'-[oxybis(ethane-2,1-diyloxy)]dipropanoic acid, poly(ethylene glycol)bis-acetic acid, polyethylene Glycol bis(carboxymethyl) ether, polyethylene glycol diacid 600, keridonic acid , 2,5 -furandicarboxylic acid, isophthalic acid, terephthalic acid, orthophthalic acid, trimesic acid, 1,4-phenylenediacetic acid, and 1,3- Finishing composition according to any one of claims 1 to 18 , selected from the group consisting of phenylene diacetic acid, and derivatives and mixtures thereof. The dicarboxylic acid has the following formula :

oxaloacetic acid;
The formula below:

tartaric acid;
The formula below:

fumaric acid;
The formula below:

mesaconic acid;
The formula below:

succinic acid or succinic acid derivatives;
The formula below:

malic acid;
The formula below:

mesooxalic acid;
The formula below:

muconic acid;
The formula below:

diglycolic acid;
The formula below:

oxydipropanoic acid;
The formula below:

2,2'-[1,2-ethanediylbis(oxy)]bisacetic acid;
The formula below:

3,3'-[1,2-ethanediylbis(oxy)]bis-propanoic acid;
The formula below:

chelidonic acid;
The formula below:

2,5-furandicarboxylic acid; and
The formula below:

1,3-phenylene diacetic acid or 1,4-phenylene diacetic acid;
The formula below:

phthalic acid and trimesic acid
Finishing composition according to any one of claims 1 to 18 , selected from the group consisting of: Finishing composition according to any one of claims 1 to 20 , wherein the polysiloxane is an amino-modified polysiloxane. A finishing composition according to any preceding claim, wherein the amount of polysiloxane in the composition is from 50 to 80 percent by weight, based on the total weight of the composition . Finishing composition according to any one of the preceding claims, wherein the amount of dicarboxylic acid in the composition is from 0.1 to 10 weight percent, based on the total weight of the composition. Finishing composition according to any one of claims 1 to 23 , wherein the emulsifier is non-ionic. Finishing composition according to any one of claims 1 to 24 , wherein the emulsifier is a water-soluble POE alkyl ether, POE alkylaryl ether or POE fatty acid ester, or a mixture thereof. Finishing composition according to any one of the preceding claims, wherein the amount of emulsifier in the composition is from 25 to 35 weight percent, based on the total weight of the composition . A fiber having a finishing coating formed from a finishing composition according to any one of claims 1 to 26, comprising polyacrylonitrile and applied to the fiber surface. Use of a finishing composition according to any one of claims 1 to 26 for the production of carbon fibers. A method of preparing a treated fiber comprising applying a finishing composition according to any one of claims 1 to 26 to a polyacrylonitrile-based fiber to form a coating on the fiber. 30. The method of claim 29 , further comprising carbonizing the fibers to form carbon fibers.